New process for lubricating



I Patented Oct. 1, 1935 UNITED STATES PATENT OFFICE No Drawing.Application October 14, 1933, Serial No. 693,680. In Germany February 7,1931 I 4 Claims. The lubrication of certain parts of valves, stopcocks,compressors, welding burners, bearing parts and the like with oils,fats, or similar organic substances which may be brought into 5 contactwith oxygen under pressure, is not permissible on account of the dangerof explosion. Since lubrication cannot be effected under, theseconditions, one must avoid wear caused by friction between the metalparts, which when worn at all are no longer capable of effecting agastight joint and make it necessary at times to replace many partswhich have been in, use for a relatively short period.

To avoid these difliculties certain lubricants of another nature thanthat of the above mentioned substances have been recommended e. g.highly concentrated aqueous solutions of inorganic salts which cannot beoxidized. These, however, have the disadvantage that they give ofi thewater, the salt separates out, and the lubricating action thereby fallsoff. Moreover, such lubricants cause corrosion.

A process has been triedfor making a new and useful product whichconsists in subjecting glycerine to temperatures of 250-260 C. inpresence of a condensing agent while a stream of an inert gas is ledthrough the reaction mixture; According tothis process a new and usefulproduct is obtained: a mixture of highly polymerized'glycerines beingfree from diand tripolymerized products, showing a brown-yellow colour,being transparent, soluble in water and alcohol, insoluble in ether,having a flash point of more than 270 C. and a refractive index of 35about 1,5. Preferably heating is continued until the product is highlyviscous.

According to the present invention it has been paste by search apparatusthese lubricants, heated to over 200 'C., are stable when subjected tosudden conglycerines.

found that such products may be used advantageously for the purpose oflubrication.

As these products are sometimes too viscous for the purpose oflubrication they are mixed with about -30% water; in order to avoidevaporation, of the water, hygroscopic products (e. g. magnesiumchloride, salts of lactic acid) are added in an amount of about '1-20%,preferably 5%. The explosive-proof lubricants obtained can be brought tothe consistency of suitable additions, for example tragacanth, talcumand the like.

As shown by experiments with suitable retact with oxygen having atemperature of 60 C. and under a pressure of 150 at., whereas oils andfats of animal, vegetable and mineral origin, and further graphite,glycerine and the like, under the same conditions explode at very muchlower pressures and temperatures.

What I claim is: 1. A lubricant comprising a mixture of highlpolymerized 'glycerines free from diand triglycerines. r

2. A lubricant according to claim 1 containing 10-30% of water.

3. A lubricant according to claim 1 containing 10-30% of water and 1-20%of a hygroscopic substance.

4. A lubricant for contacting surfaces exposed to the action of oxygenunder elevated temperature and pressure comprising a mixture of highlypolymerized glycerines free from diand tri- KARL NOACK.

